1. Michael R. Garey, David S. Johnson, Computers and Intractability:
A Guide to the Theory of NP-Completeness (Series of Books
in the Mathematical Sciences), $41.26, Paperback - 338 pages (June 1979),
W H Freeman & Co.; ISBN: 0716710455.
2. Christos H. Papadimitriou, Computational Complexity, $47.00,
Hardcover - 523 pages (January 1994) Addison-Wesley Pub Co; ISBN: 0201530821